1. Field of the Invention
This invention relates to the operation, monitoring and control of a communications system. It is of particular relevance to the operation of telecommunications networks, but is not limited to such systems.
2. Related Art
In this specification the term xe2x80x98functional elementxe2x80x99 is used to define an element of a communications system which performs some function, e.g. a switching or monitoring function, to the system itself, as distinct from an xe2x80x98application process elementxe2x80x99 which controls a number of xe2x80x9cFunctional elementsxe2x80x9d to achieve a high level function, usually requiring concerted action from several functional elements. This high-level function may be a network application such as a handover process in a mobile radio system.
In a telecommunications network the functional elements of the system are widely distributed. For example, switching functionality is required at nodes throughout the system. However, in conventional telecommunications networks application process control is concentrated, requiring a large signalling load to be carried over the telecommunications network. Despite the distributed nature of the system all elements of the network which interact must have compatible signalling formats. This is a particular problem in a cellular radio network, where mobile units made by a number of different manufacturers can turn up anywhere in the system and have to interact consistently with whichever fixed part of the network they happen to have established communication with. In such a network it is difficult to arrange for enhancement or improvements, because of the need for all signalling formats to remain compatible.
Further problems arise in known systems because of the need for measurements of network conditions e.g. link performance to be made, and the results transmitted to a control centre, either continuously or discontinuously depending on the nature of the measurements to be made and the purpose for which they are required. This places an additional signalling overhead on the network. Many measurements are often only required in specific operating circumstances. It is therefore wasteful of signalling capacity for all possible data to be transmitted when much of it is redundant. The limited signalling capacity and the number of different measurements to be made also reduce the resolution of the measurement and/or the sampling rate that can be supported.
According to a first aspect of the invention a communications system comprises a plurality of measuring means for measuring properties of the traffic carried by the communications system, and a data processing element for controlling the measuring means and receiving data from the measuring means, wherein the data processing element is arranged to selectively instruct the measuring means to transmit selected data to the data processing element.
According to a second aspect of the invention there is provided a method of measuring properties of a distributed system at remote points in a system, the system comprising a plurality of measuring means at the points where the properties are to be measured, the method comprising the steps of controlling the measuring means, and instructing the measuring means to transmit data to a data processing element.
The points at which the measuring means and data processing elements are located can be selected according to the particular functions they are required to perform. For instance, in a cellular radio network, the measurement of radio signal quality takes place at the individual base stations, but handovers and multi-casting functions require functional elements at switching points, using data from measuring means at several sites. The data processing elements may thus be located with the process control elements.
Dedicated signalling links between the process control units and the network operating units may be provided. However, if the system being controlled is a telecommunications network, the signalling may be carried over the traffic bearer links of the network. The process control elements need not be located at a node of the bearer network. Using the telecommunications network example, process control can be located at any point in the network, and for different functions may be located at different points.